Temperature sensitive reversing valve apparatus

ABSTRACT

In the present invention, a combination of four valves arranged to form a bridge is coupled to a temperature-pressure transducer that interconnects the input and output channels of the bridge according to whether the ambient environment of the transducer is relatively warm or cool. More specifically, the transducer is coupled to both a low pressure source and a high pressure source and will apply one combination of such pressures to the bridge if the transducer environment is relatively cool and another combination of such pressures if the transducer environment is relatively warm. In response to these signals, one pair of another of the valves in the bridge are closed, with the result that the connections between the bridge&#39;&#39;s input and output channels are thereby reversed.

EliiiiQ States Patent 1 Osheroff et al.

[ 1 Mar. 27, 1973 TEMPERATURE-SENSITIVE REVERSING VALVE APPARATUSInventors: Gene W. Osheroff, Las Vegas, Nev.; Laurence McGann, LosAngeles,

Calif.

Fluidtech Corporation, Inglewood, Calif.

Filed: Dec. 7, 1971 App]. No.: 205,514

Assignee:

US. Cl ..236/l C, 236/49, 236/79, 165/16 Int. Cl. ..F24f 11/06 Field ofSearch ..236/49, 1 B, l C, 81, 79; 137/597, 596.15; 165/16 l l l 1References Cited UNITED STATES PATENTS 1/1939 Riney et al ..137/597 XTEMPERATURE 2,559,588 7/1951 Blumenthal ..l37/S97 X PrimaryExaminer-William E. Wayner Attorney-Allen E. Botney 57] ABSTRACT isrelatively cool and another combination of such pressures if thetransducer environment is relatively 'warm. In response to thesesignals, one pair of another of the valves in the bridge are closed,with the result that the connections between the bridges input andoutput channels are thereby reversed.

22 Claims, 6 Drawing Figures PRESSURE TRANSDUCER l -o N Patented March27, 1973 3,722,813

\o TEMPERATURE TEMPERATURE )O "PRESSURE. 5 -PRES5URE $2 I)! mmsnucuz tTRANSDUCER. 7/ \T 11 F l \3 5e We \4 F \fbe d I f & a) 0 lo M j/NVENT'O/?5 6N 14/. OSHEROFF LAURENCE McGAN/V TEMPERATURE-SENSITIVEREVERSING VALVE APPARATUS The present invention relates to valves ingeneral and more particularly relates to a valve apparatus that issensitive to changes in ambient temperature conditions to reversegas-flow and gas-pressure connections in a system.

In systems in which gases flow and gas pressures are applied, it isoftentimes desirable, if not necessary, to reverse the connections ofsome of the ducts or channels in the system with changes in operatingconditions. It is desirable to do so, for example, in certain types ofair-conditioning systems when the conditioned air flowing thereinchanges from hot to cold or vice versa. More specifically, in order tomaximize the effectiveness and minimize the costs of suchair-conditioning systems, it is desirable as a part of their operationto first detect or determine whether hot or cold air is flowing at apoint in the system and then to connect certain ducts or channels in thesystem in one way if the system is operating in a cooling mode and toreverse those connections if the system is operating in a heating mode.

The present invention meets the above-said needs or requirements of suchsystems by providing a unique combination of temperature-pressuretransducer and reversal valve, the transducer applying one or the otherof a pair of gas-pressure signals to the reversal valve, depending,respectively, on whether the ambient environment of the transducer isrelatively hot or cold and the valve, in response to those signals,connecting a pair of input channels in one way or another to a pair ofoutput channels.

More particularly, the transducers two outputs arecoupled directly to arelatively low-pressure source and through a pair ofthermostatically-controlled valves are also coupled to a relativelyhigh-pressure source. Only one or the other of the valves is open at anyone time, with the result that when the transducer is in a relativelycool environment, one output produces the high pressure and the otheroutput produces the low pressure. On the other hand, when the transducerenvironment is relatively warm, the pressures produced at its twooutputs are reversed. The transducer valves governing these pressuresare opened and closed in response to the motion of a coiled bi-metallicstrip and, consequently, are opened and closed in response to changes inambient temperature conditions. As for the reversal valve, it comprisesfour valves connected in tandem to form a closed loop, a pair of inputchannels and a pair of output channels being connected between thevalves to form a bridge-circuit arrangement of them. The valves arepreferably disc-shaped chambers with orifices in their rooves by meansof which they are interconnected. In each valve is also located adiaphragm resting on the floor of the valve chamber and which may beraised and pressed against the roof of the chamber to cover the orificesthere, thereby closing that particular valve. By thusly closing one pairor the other of the valves diagonally opposing each other in the bridge,the connections between the input and output channels can be reversed.The diaphragms can be raised or lowered by respectively applyingrelatively high or low pressures to their undersides through orificeslocated in the floors of the valve chambers. Needless to say, byapplying the transducer output pressures to these valves, the desiredconnections between the input and the output channels can be obtained.Ultimately, therefore, the input and output channel connections aredetermined by whether the air-conditioning system is in a cooling orheating mode.

It is, therefore, an object of the present invention to provide themeans to automatically reverse certain connections in anair-conditioning system when the system shifts from a cooling mode to aheating mode, or vice versa.

It is another object of the present invention to provide apparatus todetect whether the gases flowing in a system are relatively hot or coldand to switch channel connections in the system in accordance therewith.

It is a further object of the present invention to provide an apparatusthat utilizes the temperatures and pressures of gases flowing in asystem to change connections therein.

It is an additional object of the present invention to provide the meansto maintain the effectiveness of certain types of air-conditioningsystems when they shift from the cooling mode to the heating mode, orvice versa.

The novel features which are believed to be characteristic of theinvention, both as to its organization and method of operation, togetherwith further objects and advantages thereof, will be better understoodfrom the following description considered in connection with theaccompanying drawing in which an embodiment of the invention isillustrated by way of example. It is to be expressly understood,however, that the drawing is for the purpose of illustration anddescription only and is not intended as a definition of the limits ofthe invention.

FIGS. 1a and lb are block diagrams, partly in schematic form,illustrating the basic purposes and principles of atemperature-sensitive reversing valve apparatus according to the presentinvention;

FIG. 2 is a diagram illustrating the basic structure of a preferredembodiment of a temperature-sensitive reversing valve apparatusaccording to the present invention;

FIG. 3 is a front view of the temperature-pressure transducer includedin the FIG. 2 apparatus;

FIG. 4 is a side view of the temperature-pressure transducer included inthe FIG. 2 apparatus; and

FIG. 5 is an exploded view showing in detail one of the four valvesutilized in the FIG. 2 apparatus.

To provide a preliminary understanding of the invention, reference isnow made to FIGS. la and lb of the drawing wherein the basic concept ofthe invention is depicted. The reversing valve portion of the overallapparatus is designated therein as 10, the transducer portion of theoverall apparatus is designated 11, inlet channels leadinginto'reversing valve 10 and through which gases are fed or gas pressuresapplied to it are designated I and I and channels leading out ofreversing valve 10 are designated 0 and 0 As shown in FIG. 1(a), inresponse to a gas-pressure signal S produced by transducer 11 andapplied to reversing valve 10, the reversing valve respectivelyinterconnects inlet channels I and I to outlet channels 0 and 0 In thisinstance, therefore, any gas flowing in inlet channel I enters outletchannel 0, and the same is true with respect to channels I and (I On theother hand, FIG. 1(b) shows what happens when a gas-pressure signal S isapplied by the transducer to the reversing valve. In this latterinstance, the connections between the inlet and outlet channels arereversed, that is to say, inlet channel I, is now connected to outletchannel and, similarly, inlet channel I is now connected to outletchannel 0,. In both figures, within the block designated as reversingvalve 10, the broken line indicates the above-described connectionsbetween the channels.

Considering now the invention in greater detail, reference is made toFIG. 2 wherein, in a preferred embodiment of a temperature-sensitivereversing valve apparatus according to the present invention, reversingvalve is shown to basically include a plurality of four valves,respectively designated 12-15 that are connected to one another inseries or, stated differently, in tandem by a corresponding plurality offour flow channels respectively designated 16-19. Inlet channels I, andI respectively connect to flow channels 16 and 18, whereas outletchannels 0, and 0 respectively connect to flow channels 19 and 17, withthe result, as will be recognized by those skilled in the art thatvalves 12-15, connecting flow channels 16-19, inlet channels I, and Iand outlet channels 0, and 0 combine to form a bridge-circuitarrangement. Finally, the embodiment includes still another pair ofchannels 21 and 22,

hereinafter sometimes referred to as control channels,

FIG. 2. Thus, control channel 21 interconnects valves I 13 and 15 andcontrol channel 22 interconnects valves 12 and 14. As for inlet channels23 and 24, these are connected between control channels 21 and 22,respectively, and temperature-pressure transducer 11 which, it will beremembered, produces gas-pressure signals S, and S mentioned earlier inconnection with FIGS. la and 1b.

Valves 12-15 are preferably identical to one another and, as can be seenfrom FIG. 5 wherein one of the valves is shown in greater detail, eachresembles a discshaped chamber. For sake of convenience and clarity, thevalve shown in FIG. 5 and to be described hereinbelow shall beconsidered to be valve 13 in FIG. 2, but it will be understood that thedescription will be equally applicable to all the valves. Accordingly,referring to FIG. 5, valve 13 therein basically includes a roof member13a, a floor member 13b, and a diaphragm 130. Members 13a and 13b aredisc-shaped and recessed with the result that when they are puttogether, one upon the other and sealed, they form the aforesaiddisc-shaped valve chamber.

Roof member 13a has two orifices through it designated 13d and 13e andalthough one orifice is shown located at the center of the member andthe other is shown located at its outer periphery, it must be emphasizedthat the actual location of these orifices is relatively unimportant,that is to say, that their location is merely a matter of design. Floormember 13b has one orifice through it designated 13f and here again itsactual location is only a matter of design. Floor member 13b also has acircular crevice or recess 13g located in its rim and the function ofthis recess is to properly locate and hold or, stated differently, toproperly seat diaphragm 13c when it is on the floor of the valvechamber. In this regard, diaphragm 13c has a circular lip 13h integralwith its underside which, as shown by the broken lines 131', fits intorecess 13g and thereby helps to seat the diaphragm. The diaphragmincludes another circular lip 13j that is centered on its top surface,the lip enclosing orifice 13d, as shown by broken line 13k, when thediaphragm is pressed against the roof of the valve. Finally, althoughnot essential, diaphragm 13c preferably also includes another circularlip 13! centered on its underside, lip 13l making contact with the floorof the valve, as shown by broken line 13m, when the diaphragm is seatedon member 13b. The function of lip 13] is to facilitate the separationof the diaphragm from the surface of member 13b when the operation callsfor such a separation.

Considering now the operation of the FIG. 5 valve, which is theoperation of all the valves, it will initially be assumed that no gaspressure is being applied to the underside of diaphragm 13c, which, whenapplied, is applied through orifice 13f. Accordingly, diaphragm 13c ison the floor of the valve, that is to say, it is seated on member 13b,with the result that orifices 13d and 13a are uncovered or exposedwhich, in turn, means that any gas flowing through one of these orificeswill thereafter flow through the other. Under such circumstances, thevalve is said to be open. If, now, a suitable gas pressure is appliedthrough orifice 13fto the underside of diaphragm 130, the diaphragm willbe raised and pressed against the roof of the valve chamber, that is tosay, against the undersurface of member 13a, thereby covering over orotherwise closing at least one of the two orifices there. Morespecifically, with diaphragm 13c raised against roof member 13a, orifice13d is covered over in an airtight manner and, in the subjectembodiment, so is orifice 13e. When one or both of these orifices areclosed in the manner described, there can be no flow between them andthe valve is then said to be closed." When the gas pressure that raiseddiaphragm 13c is removed, the diaphragm falls to member 13b and againbecomes seated there, with the result that the valve is now open onceagain;

At this point it would be well to refer once again to FIG. 2 and tomention that flow channel 17 therein intercouples valves 12 and 13 viaorifices 12d and 13d, that flow channel 18 intercouples valves 13 and 14via orifices 13a and 14, that flow channel 19 intercouples valves 14 and15 via orifices 14d and 15d and, finally, that flow channel 16intercouples valves 12 and 15 via orifices 12c and 15e. All of theorifices mentioned are in the rooves of the several valves, just as isshown in FIG. 5 and described in connection therewith. It should also bementioned that orifices 12f-15fare respectively in the floors of valves12-15, and that control channel 21 intercouples valves 13 and 15 viaorifices 13f and 15f while control channel 22 intercouples valves 12 and14 via orifices 12fand 14f. Of course, although not shown in FIG. 2,each of the valves therein includes a diaphragm of the kind shown inFIG. 5 that is interposed between its roof and floor members. It shouldfinally be mentioned with respect to the signals generated by transducer11 that signal S, comprises a low pressure on inlet channel 23 and ahigh pressure on inlet channel 24 and signal S, comprises a highpressure on inlet 23 and a low pressure on inlet channel 24. The mannerin which these signals are generated will be eX- plained in connectionwith the description of transducer 11 to which reference is now made.

Directing attention to FIGS. 2, 2 and 4, the transducer is shown topreferably include a pair of members 25a and 25b through which'a pair ofchannels 260 and 26b respectively extend. Tubing or similar type devicesare coupled at one end to the input ports of channels 26a and 26b, asshown in the figures, and at the other or forward end they are coupledto a relatively low pressure source (not shown), the tubes respectivelybeing designated 27a and 27b. To rigidly mount and hold members 25a and25b in place, the transducer also includes a pair of crossbars 28 and 29to which members 250 and 25b are cemented or otherwise fastened, withthe result that all four members form a rigid unit Rotatably mountedbetween crossbars 28 and 29 is a shaft 31, the ends of the shaftextending into these members as shown in the figures. A coiledbi-metallic strip 32 is mounted on shaft 31, the center of the coilbeing rigidly fastened to the shaft so that in the event of any rotativemovement of the coil, the coil and the shaft will rotate together. Theother end of the coil, designated 32a, extends from the body of the coilto member 25b where it is fixed in position just above the member bymeans of a nail or screw 33 which passes through end 32a and into member25b. A spring 34 is mounted on the nail or screw between end 32a andmember 25b, the spring forcing the coil end up against the head of thenail or screw and thereby preventing it from easily moving up and down.

Respectively connecting with channels 26a and 2612 are a pair ofidentical valves, generally designated 35 and 36, that comprise a pairof passageways or channels 35a and 36a and a plate or bar 37 that isrigidly mounted in see-saw fashion on shaft 31. For reasons that will beseen later, plate or bar 37 is made ofa magnetizable material. Channels35a and 36a respectively extend downward from the top surfaces ofmembers 25a and 25b until they connect or couple with channels 26a and26b, extending or lying over the entrances or openings to channels 35aand 36a. In order to ensure an affirmative and effective opening andclosing action for valves 35 and 36, there is preferably also provided,first, a pair of circular lips 35b and 36b that are respectively mountedon the surfaces of members 25a and 25b around the openings to channels35a and 36a and, second, a pair of felt pads 38a and 38b respectivelymounted on the underside of plate or bar ends 37a and 37b. As shown inthe figures, pads 38a and 38b respectively overlie lips 35b and 36b andeffectively cover the openings to channels 35a and 36a when they arebrought into contact with these lips.

At this point, it would be well to mention that several things can bedone and, preferably, are done to obtain a speedy response from valves35 and 36 and, therefore, from the transducer itself. First, the load oncoil 32 is reduced to a minimum and this can be achieved by keeping theweight of plate 37 and pads 38 to a practical minimum. This, in turn,can be achieved by choosing materials of relatively light weight forthem and by keeping their thicknesses to a practical minimum. Second,the spacing between the pads and the lips are made as small as possible.Third, the distance through which the ends of plate 37 travel are alsokept as small as possible, that is to say, to within necessary limitsonly, and this is done by providing another pair of lips 39a and 39b onthe top surfaces of members 25a and 25b, respectively, preferably at theouter edges thereof,

against which the ends of plate 37 respectively abut as one or the otherof the valves is closed.

Finally, a preferred embodiment of the transducer also includes a pairof magnets 41a and 41b mounted on a cross bar 42. Magnets 41a and 41bare mounted beneath plate or bar 37 intermediate shaft 31 and members25a and 25b, the primary purposes or functions of the magnets being,first, to bias plate or bar 37 to ensure that one or the other of thevalves will at all times be closed and, second, to apply slightrestraining forces on the plate or bar that will cause the valves toopen and close at slightly different temperatures, thereby helping toavoid spurious openings and closings due to slight fluctuations intemperature that may occur about the set points of the valves. By setpoint is meant the temperature at which each valve is designed to close.By way of example, if valve 36 is designed to close and valve 35 to openat 76 degrees Fahrenheit and valve 35 is designed to close and valve 36to open at 74 degrees Fahrenheit, then 76 degrees and 74 degrees arerespectively the set points for these valves and the temperaturestherebetween form what may be termed a dead band in which the states orconditions of the valves are not affected. Thus, if valve 36 is closed,which means valve 35 is open, then a momentary fluctuation of theambient temperature to 75 degrees Fahrenheit will not affect thesituation and valve 36 will remain closed. The same is true if valve 35is closed and valve 36 open. It will be recognized by those skilled inthe art that by suitable design, the set points can be brought furthertogether or apart, as desired.

In considering the operation of this transducer, it will be assumed thatit is located in a relatively high pressure environment and, aspreviously mentioned, that tubes 27a and 27b extend therefrom and coupleto a relatively low pressure environment. Thus, through valves 35 and36, channels 26a and 26b are respectively exposed to a relatively highgas pressure and through tubes 27a and 27b to a relatively low gaspressure. It will also be initially assumed, that the ambienttemperature is high enough so that valve 36 is closed, with the resultthat the output signal produced by the transducer is the aforesaidsignal 8,, namely, a high pressure in inlet channel 24 and a lowpressure in inlet channel 23. This is so because with valve 36 closed,the high pressure of the ambient environment cannot get through tochannel 26b and from there to inlet channel 23. Of

course, the reverse is true on the other side of the transducer wherevalve 35 is open.

If, now, the temperature of the environment in which the transducer islocated dropts to the set point of valve 35 or below, bi-metallic coilwill contract sufficiently to rotate shaft 31 and, therefore, plate 37,in a counterlockwise direction to thereby close valve 35 and,simultaneously therewith, open valve 36. When this occurs, the outputsignal produced by the transducer is then signal 8,, namely, a lowpressure in inlet channel 24 and a high pressure in inlet channel 23,just the reverse of the earlier signal.

The transducer will return to its former state if the ambienttemperature should rise to at least the set point of valve 36. Undersuch circumstances, bi-metallic coil 32 will expand and thereby enterinto a clockwise rotational movement which, when the set point isreached,

causes shaft 31 and, therefore, plate 37 to likewise rotate in aclockwise direction. With the clockwise rotation of plate 37, valve 36is thereby closed and, simultaneously therewith, valve 35 is opened. Atthis point, the output signal is again a high pressure in inlet channel23 and a low pressure in inlet channel 24.

Considering now the operation of reversing valve in FIGS. 2 and 5, whensignal S is applied to inlet channels 23 and 24, the low pressure ininlet channel 23 is applied through channel 21 and orifices 13f and f tothe underside of the diaphragms in valves 13 and 15, the effect thereofbeing that the diaphragms are kept seated on the floors of those valves.On the other hand, the high pressure in inlet channel 24 is appliedthrough channel 22 and orifices l2fand l4fto the underside of thediaphragms in valves 12 and 14, the effect thereof being that thediaphragms are thereby raised to and pressed against the rooves of thesevalves. In consequence of the abovev and in accordance withthedescriptive material presented hereinabove, valves 12 and 14 are closedand valves 13 and 15 are open. Accordingly, any gas entering inletchannel 1 flows into channel 16 and from there into and through valve 15to channel 19 where it exits via outlet channel 0,. By tracing the pathbetween inlet channel I; and outlet channel 0 in the same way, it wouldlikewise be found that gas flowing into inlet channel I will ultimatelyflow out of outlet channel 0 Thus, when a signal such as signal S isapplied to reversing valve 10, inlet channel I and 1 are respectfullyconnected to outlet channels 0 and O, just as it is illustrated in FIG.1(a).

If, now, instead of signal 8,, signal S is applied to inlet channels 23and 24, the high pressure in inlet channel 23 is, as before, appliedthrough channel 21 and orifices 13f and 15f to the underside of thediaphragms in valves 13 and 15. This time, however, the diaphragms areraised and pressed against the rooves of these valves to effectivelyclose them. On the other hand, due to the fact that the pressure oninlet channel 24 is now relatively low, valves 12 and 14 are open. Thus,when signal S, isapplied, a gas entering inlet channel I, must now passthrough valve 12 since valve 15 is closed and, therefore, make its exitvia outlet channel O In the same way, gas flowing in inlet channel I,can be traced through valve 14 to outlet channel 0 It can therefore beseen that signal S, reverses the connections between inlet channels Iand I and outlet channels 0 and O as illustrated in FIG. 1b.

Although a particular arrangement of the invention has been illustratedabove and described herein by way of example, it is not intended thatthe invention be limited thereto. Accordingly, the invention should beconsidered to include any and all modifications, alterations orequivalent arrangements. falling within the scope of the annexed claims.

Having thus described the invention, what is claimed is:

1. Apparatus for reversing the connections between a pair of inletchannels and a pair of outlet channels through which gases flow andgaspressures applied, the inlet and outlet channels being connected in oneway in response to a relatively warm ambient environment and in anotherway in response to a relatively cool ambient environment, said apparatuscomprising: reversing valve means including first, second, third andfourth valves, each being adapted to open and close, respectively, inresponse to first and second gas pressures applied thereto, first,second, third and fourth flow channels connected between said valves toform a closed loop arrangement in which valves and flow channels arealternately connected in the loop, the first and third of said flowchannels respectively being connected to the pair of inlet channels andthe second and fourth of said flow channels respectively being connectedto the pair of outlet channels; and temperature-pressure transducermeans coupled to said reversing valve means and to relatively high andlow gas-pressures sources, said transducer means including additionalmeans operable in response to ambient temperature conditions to apply afirst gas-pressure signal to said valves to connect the inlet and outletchannels the one way when the ambient environment is relatively warm anda second gas-pressure signal to said valves to connect the inlet andoutlet channels the other way when the ambient environment is relativelycool.

2. The apparatus defined in claim 1 wherein each valve has first andsecond orifices to which flow channels are coupled, a third orifice towhich said temperature-pressure transducer means is coupled, and adiaphragm adapted to close at least one of said first and secondorifices interposed between said first and second orifices on the onehand and said third orifice on the other hand.

3. The apparatus defined in claim 1 wherein said reversing valve meansfurther includes first and second control channels respectively havingfirst and second inputs thereto to which said first and second signalsare applied, said first control channel being connected between thefirst and third of said valves and said second control channel beingconnected between the second and fourth of said valves.

4. The apparatus defined in claim 1 wherein said first and second gaspressures are respectively low and high pressures, and wherein saidfirst signal is a first combination of said first and second gaspressures and said second signal is a second combination thereof.

5. The apparatus defined in claim 1 wherein said additional meansincludes first and second channels coupled to said low pressure source;first and second valves coupled between said first and second channels,respectively, and said high pressure source; and temperature-responsivemeans for simultaneously closing one and opening the other of saidtransducer valves.

6. The apparatus defined in claim 2 wherein said first flow channel iscoupled between the second orifices in said first and second valves,said second flow channel is coupled between the first orifices in saidsecond and third valves, said third flow channel is coupled between thesecond orifices in said third and fourth valves, and said fourth flowchannel is coupled between the first orifices in said first and fourthvalves.

7. The apparatus defined in claim 2 wherein said reversing valve meansfurther includes first and second control channels respectively havingfirst and second inputs thereto to which said first and second signalsare applied, said first control channel being coupled between the thirdorifices in said first and third valves, and said second control channelbeing coupled between the third orifices in said second and fourthvalves.

8. The apparatus defined in claim 2 wherein each of said four valves andthe diaphragm therein is adapted to seat said diaphragm over the thirdorifice in said valve in response to said first gas pressure and topress said diaphragm against said first and second orifices in saidvalve in response to said second gas pressure.

9. The apparatus defined in claim 2 wherein each of said four valvesincludes a floor member in which said third orifice is located and aroof member in which said first and second orifices are located, saidfloor member and diaphragm being adapted to normally seat said diaphragmon said floor member and operable in response to said second pressure toraise and press said diaphragm against said roof member.

10. The apparatus defined in claim 2 wherein each of said diaphragmsincludes a circular lip on its bottom side that is positioned toencircle the third orifice, and a circular lip on its topside that ispositioned to encircle the first orifice.

11. The apparatus defined in claim 5 wherein said temperature-responsivemeans includes a rotatably mounted shaft; a member mounted on said shaftand rotatable therewith, said member being adapted to simultaneouslyclose one and open the other of said transducer valves in response torotation of said shaft; and a coiled bi-metallic strip coupled to rotatesaid shaft in clockwise and counterclockwise directions in response tochanges in temperature.

12. The apparatus defined in claim 5 wherein said temperature-responsivemeans includes a coiled bimetallic element mounted to move in clockwiseand counterclockwise directions in response to changes in temperatures,and apparatus couples between said bimetallic element and saidtransducer valves, said apparatus being operable when said element movesin a clockwise direction to open and close said first and secondtransducer valves, respectively, and operable when said element moves ina counterclockwise direction to close and open said first and secondtransducer valves, respectively.

13. The apparatus defined in claim 6 wherein said reversing valve meansfurther includes first and second controlchannels respectively havingfirst and second inputs thereto to which said first and second signalsare applied, said first control channel being coupled between the thirdorifices in said first and third valves,

and said second control channel being coupled.

between the third orifices in said second and fourth valves.

14. The apparatus defined in claim 11 wherein said member is made of a.m-agnetizable material and wherein said additional means furtherincludes a pair of magnets mounted beneath said member intermediate saidshaft and valves.

15. The apparatus defined in claim 11 wherein said first and secondtransducer valves respectively include first and second passageways thatrespectively connect with said first and second channels, and whereinsaid transducer means includes elements that cooperate with said memberfor closing the entrances to said passageways.

16. The apparatus defined in claim 12 wherein said apparatus includes ashaft rotatably mounted between said transducer valves and coupled tosaid bi-metallic element to rotate with the movement therewith; and alate mounted in see-saw fashion on said shaft and exendmg over saidtransducer valves, said plate rotating with said shaft to close one andopen the other of said transducer valves.

17. The apparatus defined in claim 13 wherein each of said four valvesand the diaphragm therein is adapted to seat said diaphragm over thethird orifice in said valve in response to said first gas pressure andto press said diaphragm against said first and second orifices in saidvalve in response to said second pressure.

18. The apparatus defined in claim 15 wherein said member is a platemounted in see-saw fashion on said shaft and extending over saidtransducer valves, and wherein said elements include felt-like padsrespectively mounted on the ends of said plate on the underside thereofto cover the entrances to said passageways when moved by said plate intocontact therewith.

19. The apparatus defined in claim 18 wherein said plate is made of amagnetizable material and wherein said additional means further includesa pair of mag nets mounted beneath and in proximity to said plateintermediate said shaft and said transducer valves.

20. Gas-flow apparatus connected between first and second inlet channelsand first and second outlet channels, said apparatus comprising: firstvalve means operable in response to a first gas pressure signal torespectively couple the first and second inlet channels to the first andsecond outlet channels; second valve means operable in response to asecond gas pressure signal to respectively couple the first and secondinlet channels to the second and first outlet channels; and

.temperature-pressure transducer means coupled to said first and secondvalve means and to relatively high and low gas pressure sources, saidtransducer means including additional means operable in response toambient temperature conditions to produce said first gas pressure signaland apply it to said first valve means and said second gas pressuresignal and apply it to said second valve means.

21. The apparatus defined in claim 20 wherein said first and secondvalve means include a plurality of valves and gas flow channelsinterconnected to form a four-terminal bridge circuit between the inletand outlet channels.

22. In an air-conditioning system, apparatus coupled between first andsecond inlet channels and first and second outlet channels, saidapparatus being operable in response to changes in the operatingconditions of the air-conditioning system to change the connectionsbetween said inlet and outlet channels, said apparatus comprising: valvemeans operable in response to a first gas pressure signal torespectively connect the first and second inlet channels to the firstand second outlet channels and operable in response to a second gaspressure signal to respectively connect the first and second inletchannels to the second and first outlet channels; andtemperature-responsive means for producing said first gas pressuresignal when the air-conditioning system is in a heating mode and saidsecond gas pressure signal when the air-conditioning system is in acooling mode, said temperature-responsive means being coupled to saidvalve means to apply said first and second signals thereto.

1. Apparatus for reversing the connections between a pair of inletchannels and a pair of outlet channels through which gases flow and gaspressures applied, the inlet and outlet channels being connected in oneway in response to a relatively warm ambient environment and in anotherway in response to a relatively cool ambient environment, said apparatuscomprising: reversing valve means including first, second, third andfourth valves, each being adapted to open and close, respectively, inresponse to first and second gas pressures applied thereto, first,second, third and fourth flow channels connected between said valves toform a closed loop arrangement in which valves and flow channels arealternately connected in the loop, the first and third of said flowchannels respectively being connected to the pair of inlet channels andthe second and fourth of said flow channels respectively being connectedto the pair of outlet channels; and temperature-pressure transducermeans coupled to said reversing valve means and to relatively high andlow gaspressures sources, said transducer means including additionalmeans operable in response to ambient temperature conditions to apply afirst gas-pressure signal to said valves to connect the inlet and outletchannels the one way when the ambient environment is relatively warm anda second gas-pressure signal to said valves to connect the inlet andoutlet channels the other way when the ambient environment is relativelycool.
 2. The apparatus defined in claim 1 wherein each valve has firstand second orifices to which flow channels are coupled, a third orificeto which said temperature-pressure transducer means is coupled, and adiaphragm adapted to close at least one of said first and secondOrifices interposed between said first and second orifices on the onehand and said third orifice on the other hand.
 3. The apparatus definedin claim 1 wherein said reversing valve means further includes first andsecond control channels respectively having first and second inputsthereto to which said first and second signals are applied, said firstcontrol channel being connected between the first and third of saidvalves and said second control channel being connected between thesecond and fourth of said valves.
 4. The apparatus defined in claim 1wherein said first and second gas pressures are respectively low andhigh pressures, and wherein said first signal is a first combination ofsaid first and second gas pressures and said second signal is a secondcombination thereof.
 5. The apparatus defined in claim 1 wherein saidadditional means includes first and second channels coupled to said lowpressure source; first and second valves coupled between said first andsecond channels, respectively, and said high pressure source; andtemperature-responsive means for simultaneously closing one and openingthe other of said transducer valves.
 6. The apparatus defined in claim 2wherein said first flow channel is coupled between the second orificesin said first and second valves, said second flow channel is coupledbetween the first orifices in said second and third valves, said thirdflow channel is coupled between the second orifices in said third andfourth valves, and said fourth flow channel is coupled between the firstorifices in said first and fourth valves.
 7. The apparatus defined inclaim 2 wherein said reversing valve means further includes first andsecond control channels respectively having first and second inputsthereto to which said first and second signals are applied, said firstcontrol channel being coupled between the third orifices in said firstand third valves, and said second control channel being coupled betweenthe third orifices in said second and fourth valves.
 8. The apparatusdefined in claim 2 wherein each of said four valves and the diaphragmtherein is adapted to seat said diaphragm over the third orifice in saidvalve in response to said first gas pressure and to press said diaphragmagainst said first and second orifices in said valve in response to saidsecond gas pressure.
 9. The apparatus defined in claim 2 wherein each ofsaid four valves includes a floor member in which said third orifice islocated and a roof member in which said first and second orifices arelocated, said floor member and diaphragm being adapted to normally seatsaid diaphragm on said floor member and operable in response to saidsecond pressure to raise and press said diaphragm against said roofmember.
 10. The apparatus defined in claim 2 wherein each of saiddiaphragms includes a circular lip on its bottom side that is positionedto encircle the third orifice, and a circular lip on its topside that ispositioned to encircle the first orifice.
 11. The apparatus defined inclaim 5 wherein said temperature-responsive means includes a rotatablymounted shaft; a member mounted on said shaft and rotatable therewith,said member being adapted to simultaneously close one and open the otherof said transducer valves in response to rotation of said shaft; and acoiled bi-metallic strip coupled to rotate said shaft in clockwise andcounterclockwise directions in response to changes in temperature. 12.The apparatus defined in claim 5 wherein said temperature-responsivemeans includes a coiled bi-metallic element mounted to move in clockwiseand counterclockwise directions in response to changes in temperatures,and apparatus couples between said bi-metallic element and saidtransducer valves, said apparatus being operable when said element movesin a clockwise direction to open and close said first and secondtransducer valves, respectively, and operable when said element moves ina counterclockwise direction to close and open said first and seCondtransducer valves, respectively.
 13. The apparatus defined in claim 6wherein said reversing valve means further includes first and secondcontrol channels respectively having first and second inputs thereto towhich said first and second signals are applied, said first controlchannel being coupled between the third orifices in said first and thirdvalves, and said second control channel being coupled between the thirdorifices in said second and fourth valves.
 14. The apparatus defined inclaim 11 wherein said member is made of a magnetizable material andwherein said additional means further includes a pair of magnets mountedbeneath said member intermediate said shaft and valves.
 15. Theapparatus defined in claim 11 wherein said first and second transducervalves respectively include first and second passageways thatrespectively connect with said first and second channels, and whereinsaid transducer means includes elements that cooperate with said memberfor closing the entrances to said passageways.
 16. The apparatus definedin claim 12 wherein said apparatus includes a shaft rotatably mountedbetween said transducer valves and coupled to said bi-metallic elementto rotate with the movement therewith; and a plate mounted in see-sawfashion on said shaft and extending over said transducer valves, saidplate rotating with said shaft to close one and open the other of saidtransducer valves.
 17. The apparatus defined in claim 13 wherein each ofsaid four valves and the diaphragm therein is adapted to seat saiddiaphragm over the third orifice in said valve in response to said firstgas pressure and to press said diaphragm against said first and secondorifices in said valve in response to said second pressure.
 18. Theapparatus defined in claim 15 wherein said member is a plate mounted insee-saw fashion on said shaft and extending over said transducer valves,and wherein said elements include felt-like pads respectively mounted onthe ends of said plate on the underside thereof to cover the entrancesto said passageways when moved by said plate into contact therewith. 19.The apparatus defined in claim 18 wherein said plate is made of amagnetizable material and wherein said additional means further includesa pair of magnets mounted beneath and in proximity to said plateintermediate said shaft and said transducer valves.
 20. Gas-flowapparatus connected between first and second inlet channels and firstand second outlet channels, said apparatus comprising: first valve meansoperable in response to a first gas pressure signal to respectivelycouple the first and second inlet channels to the first and secondoutlet channels; second valve means operable in response to a second gaspressure signal to respectively couple the first and second inletchannels to the second and first outlet channels; andtemperature-pressure transducer means coupled to said first and secondvalve means and to relatively high and low gas pressure sources, saidtransducer means including additional means operable in response toambient temperature conditions to produce said first gas pressure signaland apply it to said first valve means and said second gas pressuresignal and apply it to said second valve means.
 21. The apparatusdefined in claim 20 wherein said first and second valve means include aplurality of valves and gas flow channels interconnected to form afour-terminal bridge circuit between the inlet and outlet channels. 22.In an air-conditioning system, apparatus coupled between first andsecond inlet channels and first and second outlet channels, saidapparatus being operable in response to changes in the operatingconditions of the air-conditioning system to change the connectionsbetween said inlet and outlet channels, said apparatus comprising: valvemeans operable in response to a first gas pressure signal torespectively connect the first and second inlet channels to the firstand second outlet channels and operable in response to a second gasprEssure signal to respectively connect the first and second inletchannels to the second and first outlet channels; andtemperature-responsive means for producing said first gas pressuresignal when the air-conditioning system is in a heating mode and saidsecond gas pressure signal when the air-conditioning system is in acooling mode, said temperature-responsive means being coupled to saidvalve means to apply said first and second signals thereto.